The present invention is directed toward methods and apparatus for whitening a person's teeth and more particularly, toward a method where a carrier has bleaching agents applied thereto and the carrier is applied to a person's teeth whereupon the teeth are exposed to a light source in order to enhance the effectiveness of the bleaching agents.
Dentists, like other health care professionals, often seek ways in which to improve instruments and procedures in order to provide better care for their patients. For example, dentists have experimented with various procedures for whitening teeth. One such procedure involves dipping a gauze strip into a bleaching material, applying the strip to a patient's tooth, and then exposing the covered tooth to a light source. This procedure, however, is not very effective because the amount of light which passes through the gauze strip is minimal since it is not transparent. A further limitation of this procedure is that because only one tooth is whitened at a time, the procedure is time-consuming, thereby increasing the patient's discomfort and exposure to the light source.
Currently, dentists whiten a patient's teeth by preparing a peroxide solution and coating the teeth with the solution. Once the solution is placed on the teeth, the teeth are exposed to a heat lamp or a laser light in order to heat the peroxide and to accelerate the bleaching process. In order to protect the patient's gums, a rubber sheet, Vaseline, or a light cured gel may be placed on the gums.
There are several disadvantages with the above-described process. For example, the rubber sheet placed over the patient's gums may stretch so that the peroxide solution leaks around the rubber sheet, exposing the patient's gums to the peroxide, thereby causing the patient discomfort. Also, this method cannot be performed on the upper set of teeth and the lower set of teeth simultaneously. Rather, only one set of teeth may be whitened at a time. Another disadvantage is that if a heat lamp is used a substantial amount of time is required in order to effectively bleach the teeth. Thus, the patient is exposed to the lamp for a great deal of time. This can cause extreme discomfort and inconvenience to the patient. Furthermore, the peroxide solution often times cannot be concentrated on the teeth. That is, the solution may drip off of the teeth if too much of the solution is applied or the solution may dry out if too little of the solution is applied.
Another method of whitening teeth is disclosed in U.S. Pat. No. 5,645,428 to Yarborough. This patent discloses using a laser light to activate bleaching agents applied to a patient's teeth. A mixture of peroxide and a first catalyst is prepared and then applied to the teeth. The teeth are then exposed to a laser light which activates the peroxide and catalyst to accelerate the bleaching process without heat. A second mixture of peroxide and a catalyst is then prepared and applied to the teeth. Again, the teeth are exposed to a laser light which heat activates the second mixture to accelerate the bleaching process. This process, however, increases the patient's exposure to laser light.
In yet another system, a peroxide solution may be combined with a gel which acts as a carrier. The mixture is then applied to a person's teeth which are then exposed to a light source. This system may be used by a person without the aid of a dentist or other medical personnel. That is, the peroxide-gel solution may be placed within a plastic mouthguard, such as shown in U.S. Pat. No. 4,990,089 to Munro, which is worn by a person overnight. A problem with this system is that the peroxide-gel solution decreases the effectiveness of the peroxide because generally these solutions are weak.
Also, the use of gel, in any dental office system, decreases the effectiveness of the peroxide because of the gel's opacity. That is, light is not able to pass through to all of the peroxide because of the opacity of the gel. Also, the gel prevents full contact of the tooth with the peroxide solution, thereby decreasing the effectiveness of the peroxide solution.
A home system for whitening teeth is disclosed in U.S. Pat. No. 5,891,453 to Sagel et al. The delivery system described in this patent comprises a strip of flexible material onto which the user may place a quantity of a tooth whitening substance. The flexible strip along with the tooth whitening substance is then placed on the surface of the teeth and is allowed to remain in place for a sufficient period of time to allow the active ingredient within the substance to act on the surface of the teeth. Because the system described in this patent is intended for home use, the concentration of the whitening substance must be relatively low and there is no suggestion of applying ultraviolet light or any other light in order to enhance the whitening function.